Atchison
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Atchison clear sky chart from 2005-11-06 to 2024-03-01.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	12% 7% 3 6% 5% 3 4 4 5% 7% 44%	78605
	Night	11% 7% 3 6% 4 2 4 4 5% 6% 48%	80852
Transparency	Day	28% 34% 8% 17% 10% 2	78328
	Night	27% 33% 8% 18% 12% 2	80649
Seeing	Day	15% 8% 29% 28% 16% 4	14681
	Night	14% 9% 32% 33% 12% 1	24757

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	14% 9% 4 9% 6% 2 4 4 6% 7% 34%	2847
	11th to 20th	Day	9% 12% 4 9% 7% 4 8% 3 3 5% 37%	2850
	21st to end	Day	13% 13% 7% 10% 6% 3 4 4 4 6% 29%	3135
February	1st to 10th	Day	13% 10% 4 8% 6% 3 4 3 5% 6% 37%	1710
	11th to 20th	Day	11% 9% 5% 6% 5% 2 5% 3 5% 8% 42%	1664
	21st to end	Day	11% 9% 4 6% 4 2 3 4 5% 6% 45%	1609
March	1st to 10th	Day	13% 9% 3 6% 5% 3 4 4 5% 5% 43%	1980
	11th to 20th	Day	19% 12% 3 6% 3 2 3 4 5% 6% 36%	1980
	21st to end	Day	20% 12% 4 7% 6% 3 4 4 4 6% 30%	2178
April	1st to 10th	Day	14% 8% 2 5% 5% 2 4 3 4 7% 45%	2063
	11th to 20th	Day	16% 9% 3 5% 5% 3 4 4 5% 7% 40%	2134
	21st to end	Day	22% 6% 3 5% 5% 2 4 4 5% 7% 37%	2335
May	1st to 10th	Day	17% 8% 3 7% 6% 3 5% 4 4 7% 37%	2340
	11th to 20th	Day	15% 7% 2 6% 5% 3 5% 5% 5% 8% 40%	2302
	21st to end	Day	15% 7% 3 6% 5% 4 5% 5% 6% 8% 37%	2583
June	1st to 10th	Day	7% 3 2 4 5% 3 6% 5% 6% 8% 50%	2520
	11th to 20th	Day	8% 3 2 5% 5% 3 5% 5% 6% 9% 48%	2520
	21st to end	Day	7% 3 2 4 5% 3 6% 6% 6% 9% 50%	2516
July	1st to 10th	Day	9% 4 2 4 4 3 5% 5% 7% 10% 46%	2340
	11th to 20th	Day	6% 3 2 5% 5% 3 5% 5% 6% 8% 52%	2340
	21st to end	Day	9% 4 3 4 4 3 4 5% 6% 10% 49%	2546
August	1st to 10th	Day	7% 5% 2 5% 5% 4 5% 6% 7% 10% 44%	2328
	11th to 20th	Day	9% 5% 2 5% 5% 3 4 5% 5% 7% 50%	2301
	21st to end	Day	9% 4 2 3 4 3 3 4 4 8% 55%	2462
September	1st to 10th	Day	13% 4 2 3 4 3 3 4 6% 6% 52%	2149
	11th to 20th	Day	10% 5% 2 5% 5% 3 5% 5% 5% 5% 50%	1980
	21st to end	Day	9% 4 1 3 4 2 4 4 4 6% 58%	1980
October	1st to 10th	Day	13% 6% 2 5% 3 3 3 4 5% 7% 51%	1805
	11th to 20th	Day	13% 5% 2 5% 3 2 3 3 4 6% 54%	1800
	21st to end	Day	14% 7% 2 4 5% 2 3 3 4 6% 49%	1980
November	1st to 10th	Day	9% 5% 2 3 4 3 4 3 4 7% 56%	1808
	11th to 20th	Day	13% 6% 2 4 4 2 4 4 5% 5% 52%	1647
	21st to end	Day	15% 10% 3 4 2 2 3 4 4 7% 46%	1520
December	1st to 10th	Day	10% 6% 3 6% 6% 3 5% 6% 5% 6% 44%	1520
	11th to 20th	Day	12% 9% 3 7% 6% 3 4 4 3 6% 42%	1918
	21st to end	Day	16% 13% 7% 13% 6% 3 4 4 4 4 25%	2915
January	1st to 10th	Night	9% 8% 4 14% 7% 3 4 4 4 6% 36%	4108
	11th to 20th	Night	10% 10% 4 6% 4 3 8% 5% 5% 4 40%	4120
	21st to end	Night	15% 12% 5% 10% 5% 3 4 4 4 5% 33%	4532
February	1st to 10th	Night	11% 11% 4 8% 5% 3 4 4 5% 5% 39%	2470
	11th to 20th	Night	11% 8% 3 6% 6% 2 5% 4 5% 7% 43%	2403
	21st to end	Night	11% 8% 3 5% 4 3 3 4 5% 6% 48%	1862
March	1st to 10th	Night	10% 7% 4 5% 4 2 4 4 4 7% 50%	1986
	11th to 20th	Night	17% 8% 3 5% 4 3 3 4 4 6% 42%	1980
	21st to end	Night	23% 9% 3 6% 6% 3 4 4 5% 6% 33%	2178
April	1st to 10th	Night	11% 5% 3 5% 3 2 4 3 5% 7% 52%	1895
	11th to 20th	Night	14% 7% 3 4 5% 2 3 3 4 6% 48%	1775
	21st to end	Night	17% 6% 2 5% 5% 3 4 4 4 7% 43%	1622
May	1st to 10th	Night	16% 6% 3 5% 5% 3 4 5% 6% 7% 41%	1620
	11th to 20th	Night	15% 5% 2 4 4 2 4 4 5% 7% 48%	1593
	21st to end	Night	11% 4 2 6% 5% 3 5% 5% 5% 8% 47%	1689
June	1st to 10th	Night	4 2 1 3 3 3 4 6% 5% 10% 57%	1440
	11th to 20th	Night	6% 4 1 3 4 2 5% 5% 6% 9% 55%	1440
	21st to end	Night	4 2 2 4 3 2 4 5% 4 10% 62%	1440
July	1st to 10th	Night	7% 3 2 4 4 3 4 5% 7% 10% 52%	1618
	11th to 20th	Night	3 2 1 3 4 1 4 4 7% 10% 61%	1620
	21st to end	Night	6% 3 3 4 4 3 4 4 8% 9% 53%	1772
August	1st to 10th	Night	4 2 1 4 4 2 4 5% 7% 10% 55%	1611
	11th to 20th	Night	7% 4 2 4 4 2 4 5% 4 7% 58%	1600
	21st to end	Night	6% 4 1 3 4 3 3 3 5% 8% 60%	1894
September	1st to 10th	Night	10% 3 2 4 4 2 4 4 4 6% 57%	1808
	11th to 20th	Night	9% 4 1 4 4 2 4 4 6% 6% 55%	1980
	21st to end	Night	7% 4 2 3 4 2 4 4 4 6% 60%	1980
October	1st to 10th	Night	13% 5% 2 4 4 2 3 3 4 6% 56%	2136
	11th to 20th	Night	14% 4 2 3 4 2 4 3 3 5% 56%	2160
	21st to end	Night	15% 7% 2 4 3 2 2 3 3 4 53%	2376
November	1st to 10th	Night	7% 4 2 3 3 2 3 3 4 6% 62%	2267
	11th to 20th	Night	11% 5% 2 4 4 2 3 3 4 6% 55%	2531
	21st to end	Night	14% 7% 3 4 3 2 3 3 4 5% 52%	2660
December	1st to 10th	Night	9% 8% 3 5% 5% 3 5% 4 4 7% 48%	2660
	11th to 20th	Night	12% 8% 3 6% 5% 2 3 4 4 6% 47%	3279
	21st to end	Night	20% 16% 6% 9% 4 2 3 3 3 4 30%	4747

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	40% 25% 10% 19% 6%	2848
	11th to 20th	Day	41% 24% 11% 15% 8%	2850
	21st to end	Day	46% 21% 9% 13% 10%	3135
February	1st to 10th	Day	32% 34% 7% 17% 8% 2	1710
	11th to 20th	Day	28% 35% 9% 17% 9% 2	1673
	21st to end	Day	25% 33% 9% 18% 12% 2	1609
March	1st to 10th	Day	29% 35% 8% 16% 10% 1	1980
	11th to 20th	Day	37% 36% 5% 15% 6% 1	1980
	21st to end	Day	38% 36% 10% 11% 4 1	2178
April	1st to 10th	Day	26% 35% 8% 16% 13% 2	2063
	11th to 20th	Day	31% 35% 6% 15% 11% 1	2134
	21st to end	Day	31% 36% 8% 18% 6% 1	2335
May	1st to 10th	Day	34% 37% 8% 12% 8% 1	2340
	11th to 20th	Day	28% 37% 9% 16% 10%	2306
	21st to end	Day	32% 37% 9% 12% 7% 2	2583
June	1st to 10th	Day	21% 37% 11% 21% 8% 1	2520
	11th to 20th	Day	21% 37% 8% 20% 12% 1	2520
	21st to end	Day	20% 36% 8% 21% 12% 3	2516
July	1st to 10th	Day	23% 38% 10% 18% 9% 2	2276
	11th to 20th	Day	21% 38% 9% 16% 14% 3	2271
	21st to end	Day	22% 37% 8% 22% 10% 1	2405
August	1st to 10th	Day	20% 38% 11% 18% 12% 1	2314
	11th to 20th	Day	22% 35% 6% 21% 14% 1	2301
	21st to end	Day	16% 36% 7% 19% 16% 6%	2462
September	1st to 10th	Day	23% 36% 6% 16% 14% 6%	2149
	11th to 20th	Day	26% 36% 6% 16% 15% 1	1980
	21st to end	Day	17% 36% 6% 23% 17% 2	1980
October	1st to 10th	Day	16% 35% 8% 22% 17% 1	1805
	11th to 20th	Day	26% 36% 5% 17% 14% 3	1800
	21st to end	Day	26% 36% 9% 14% 13% 3	1980
November	1st to 10th	Day	17% 40% 8% 20% 13% 2	1808
	11th to 20th	Day	22% 38% 6% 19% 13% 1	1647
	21st to end	Day	24% 38% 8% 17% 13% 1	1520
December	1st to 10th	Day	24% 39% 11% 18% 8%	1520
	11th to 20th	Day	31% 31% 11% 21% 5%	1915
	21st to end	Day	51% 24% 8% 12% 4 1	2915
January	1st to 10th	Night	41% 25% 10% 16% 8%	4108
	11th to 20th	Night	37% 24% 10% 19% 11% 1	4120
	21st to end	Night	47% 21% 11% 13% 7% 1	4532
February	1st to 10th	Night	32% 34% 5% 15% 11% 3	2470
	11th to 20th	Night	27% 35% 8% 16% 12% 3	2404
	21st to end	Night	26% 33% 6% 18% 14% 4	1862
March	1st to 10th	Night	23% 35% 8% 18% 12% 2	1986
	11th to 20th	Night	29% 36% 8% 16% 9% 1	1980
	21st to end	Night	36% 36% 9% 12% 6% 1	2178
April	1st to 10th	Night	21% 35% 8% 17% 16% 3	1895
	11th to 20th	Night	27% 35% 6% 19% 12% 3	1775
	21st to end	Night	28% 36% 8% 17% 10% 1	1622
May	1st to 10th	Night	30% 36% 9% 14% 10% 1	1620
	11th to 20th	Night	25% 37% 9% 15% 13% 1	1594
	21st to end	Night	24% 37% 12% 17% 8% 2	1690
June	1st to 10th	Night	18% 37% 12% 22% 8% 2	1440
	11th to 20th	Night	17% 37% 11% 20% 13% 2	1440
	21st to end	Night	15% 35% 9% 22% 16% 3	1440
July	1st to 10th	Night	19% 38% 10% 20% 11% 2	1573
	11th to 20th	Night	12% 38% 11% 19% 16% 4	1566
	21st to end	Night	18% 37% 8% 22% 14% 1	1673
August	1st to 10th	Night	14% 36% 12% 23% 12% 2	1601
	11th to 20th	Night	18% 36% 7% 22% 16% 2	1600
	21st to end	Night	13% 35% 6% 20% 18% 7%	1894
September	1st to 10th	Night	18% 35% 5% 18% 16% 8%	1808
	11th to 20th	Night	22% 36% 6% 17% 16% 3	1980
	21st to end	Night	15% 35% 6% 19% 22% 3	1980
October	1st to 10th	Night	15% 36% 6% 20% 20% 3	2136
	11th to 20th	Night	24% 36% 5% 17% 14% 5%	2160
	21st to end	Night	25% 36% 7% 14% 16% 2	2376
November	1st to 10th	Night	14% 40% 9% 19% 14% 4	2267
	11th to 20th	Night	20% 39% 7% 20% 12% 2	2531
	21st to end	Night	21% 38% 7% 19% 12% 3	2660
December	1st to 10th	Night	25% 39% 8% 19% 8% 1	2660
	11th to 20th	Night	26% 31% 9% 26% 8%	3281
	21st to end	Night	49% 25% 6% 15% 5% 1	4747

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	21% 13% 36% 21% 9%	270
	11th to 20th	Day	22% 18% 40% 17% 3	270
	21st to end	Day	15% 10% 49% 21% 4	297
February	1st to 10th	Day	20% 17% 42% 17% 2 1	270
	11th to 20th	Day	17% 16% 46% 14% 7%	270
	21st to end	Day	14% 20% 44% 17% 4	225
March	1st to 10th	Day	15% 16% 47% 20% 2	240
	11th to 20th	Day	31% 13% 33% 18% 5% 1	240
	21st to end	Day	34% 17% 31% 13% 3 1	264
April	1st to 10th	Day	23% 15% 36% 19% 7%	323
	11th to 20th	Day	21% 11% 37% 24% 6% 1	412
	21st to end	Day	24% 12% 35% 18% 10% 1	595
May	1st to 10th	Day	21% 12% 37% 21% 7% 2	603
	11th to 20th	Day	20% 10% 29% 28% 12% 2	625
	21st to end	Day	18% 6% 30% 26% 16% 4	679
June	1st to 10th	Day	6% 5% 21% 33% 27% 8%	630
	11th to 20th	Day	7% 4 29% 36% 19% 5%	630
	21st to end	Day	8% 5% 33% 37% 15% 2	630
July	1st to 10th	Day	11% 2 14% 32% 31% 10%	621
	11th to 20th	Day	6% 2 18% 40% 27% 8%	618
	21st to end	Day	10% 2 15% 37% 30% 7%	684
August	1st to 10th	Day	9% 2 14% 38% 31% 6%	626
	11th to 20th	Day	10% 2 16% 38% 25% 8%	615
	21st to end	Day	10% 2 13% 33% 31% 10%	581
September	1st to 10th	Day	15% 2 18% 33% 27% 5%	439
	11th to 20th	Day	6% 3 22% 34% 26% 7%	270
	21st to end	Day	14% 6% 28% 32% 15% 5%	270
October	1st to 10th	Day	15% 7% 26% 28% 19% 6%	270
	11th to 20th	Day	10% 15% 45% 23% 6% 1	270
	21st to end	Day	19% 13% 37% 22% 7% 2	297
November	1st to 10th	Day	14% 7% 41% 26% 9% 2	270
	11th to 20th	Day	15% 15% 39% 21% 9% 1	270
	21st to end	Day	21% 10% 36% 24% 9% 1	270
December	1st to 10th	Day	8% 15% 40% 26% 9% 2	270
	11th to 20th	Day	21% 13% 35% 22% 7% 1	270
	21st to end	Day	22% 20% 39% 18% 1	297
January	1st to 10th	Night	13% 13% 37% 29% 7% 1	950
	11th to 20th	Night	16% 14% 39% 25% 6% 1	950
	21st to end	Night	15% 11% 41% 29% 4	1045
February	1st to 10th	Night	17% 13% 43% 25% 3	950
	11th to 20th	Night	16% 13% 38% 29% 4	929
	21st to end	Night	16% 14% 41% 22% 6% 1	606
March	1st to 10th	Night	14% 13% 42% 25% 5%	542
	11th to 20th	Night	20% 9% 34% 30% 6% 1	540
	21st to end	Night	27% 10% 35% 24% 4	594
April	1st to 10th	Night	14% 11% 42% 27% 6%	540
	11th to 20th	Night	17% 13% 35% 29% 6%	533
	21st to end	Night	19% 8% 38% 27% 7% 1	540
May	1st to 10th	Night	17% 8% 32% 34% 8% 1	540
	11th to 20th	Night	18% 5% 31% 34% 12%	531
	21st to end	Night	13% 6% 28% 38% 14% 2	584
June	1st to 10th	Night	5% 3 21% 44% 25% 1	540
	11th to 20th	Night	8% 3 25% 47% 16% 2	540
	21st to end	Night	4 4 34% 43% 15%	540
July	1st to 10th	Night	8% 1 12% 44% 32% 3	525
	11th to 20th	Night	3 1 16% 50% 29% 2	522
	21st to end	Night	8% 2 13% 49% 28% 1	591
August	1st to 10th	Night	5% 1 14% 47% 31% 2	537
	11th to 20th	Night	7% 3 12% 45% 31% 3	534
	21st to end	Night	8% 2 12% 42% 32% 4	594
September	1st to 10th	Night	13% 3 19% 40% 23% 3	540
	11th to 20th	Night	10% 1 21% 42% 24% 2	540
	21st to end	Night	7% 3 27% 43% 18% 2	540
October	1st to 10th	Night	14% 7% 26% 32% 19% 2	696
	11th to 20th	Night	16% 9% 39% 29% 7% 1	720
	21st to end	Night	19% 10% 35% 27% 9%	792
November	1st to 10th	Night	9% 11% 33% 37% 10% 1	787
	11th to 20th	Night	13% 11% 39% 29% 7%	950
	21st to end	Night	17% 11% 37% 28% 8%	950
December	1st to 10th	Night	14% 12% 35% 31% 7% 1	950
	11th to 20th	Night	18% 9% 40% 27% 6%	950
	21st to end	Night	18% 15% 37% 26% 4	1045

Page generated at 2024-02-27 05:30:14. Version ac07

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